概念不清呀,过程省略向量2字：AM=2AN=2(xAB+yAC),而：MB=AB-AM,CM=AM-ACCM与MB是同向向量,故满足关系：MB=kCM,即：AB-AM=k(AM-AC)即：(k+1)AM=AB+kAC=2(k+1)(xAB+yAC),即：2(k+1)x=1,2(k+1)y=k即：x=1/(2(k+1)),y=k/...